Fistulas are abnormal tunnels between two tissues within the body. These pathogenic ducts can lead to health problems if left untreated. They commonly occur in the gastrointestinal tract as well as biliary conduits, and can also be seen in the vascular system. If left untreated, fistulas can cause abscesses, infections and other complications. Typically, a fistula that is unable to heal or which develops abscesses, infections, or other complications requires treatment through an invasive surgical procedure. Currently, fistula treatment requires extensive surgery under general anesthesia, followed by several weeks of recuperation. Such procedures are also typically associated with high patient costs. Further, some patients have poor health conditions and are poor candidates for such surgeries in the first place.
Various forms of glues have been explored for use in less invasive tissue closure methods. Cyanoacrylates are the compounds most commonly used for these purposes. These compounds are generally liquid monomers that polymerize into longer polymer chains upon exposure to moisture. There are several varieties designed for medical use in humans. Problems in using these compounds to treat a fistula arise from the difficulty in maintaining precise control of the glue. In some circumstances, the glue can flow away from the targeted treatment site before setting, which risks damaging, obstructing, or occluding non-targeted tissues or anatomical structures. Likewise, the glue delivery device can become entrapped against or within the treatment site if the glue is injected too slowly relative to the polymerization rate of the glue.